π-Conjugated Aligned Polar [CO₃] Triangulars Synergizing Hydroxylation Enables Stress-Enhanced Geometric-Electronic...

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Piezocatalytic water splitting is a sustainable method for hydrogen production.
• Challenges include weak material polarity and slow charge separation kinetics under mechanical stress.

Purpose of the Study:

• To develop a robust piezocatalyst for efficient hydrogen evolution.
• To investigate the role of polar groups and surface hydroxylation in enhancing piezocatalytic activity.

Main Methods:

• Scalable synthesis of hydroxylated Bi2O2CO3 (BOC) with noncentrosymmetric (NCS) planar triangular [CO3] groups.
• Characterization of structural, electronic, and polarization properties under mechanical stress.
• Evaluation of piezocatalytic hydrogen evolution rates and mechanical-to-hydrogen (MTH) energy conversion efficiency.

Main Results:

• Hydroxylated BOC exhibits strong spontaneous polarization due to aligned NCS planar [CO3] groups.
• Mechanical stress induces anisotropic lattice distortion, amplifying the internal electric field for enhanced charge separation.
• Achieved an ultrahigh piezocatalytic H2 evolution rate of 3055 µmol·g⁻¹·h⁻¹ and 0.31% MTH efficiency.
• Demonstrated robust performance in pure water, rainwater, seawater, and antibiotic wastewater.

Conclusions:

• Polar group design is a viable strategy for developing advanced piezocatalysts.
• Hydroxylated BOC is a highly effective catalyst for sustainable hydrogen production via piezocatalysis.
• The catalyst shows potential for real-world applications in diverse aquatic environments.